Xylem BMAID R4 - Manual (Page 4)

PAGE 4
Residential Water Systems
CentriPro
motor CoolING, tEmpEraturE aND tImE ratINGS
All 4 inch CentriPro motors may be operated continuously in water up to 86º F. Optimum
service life will be attained by maintaining a minimum flow rate past the motor of .25 feet
per second. Use a Flow Sleeve if velocity is below the .25’/sec, if the well is top feeding or
when the pump is used in a large body of water or large tank.
Six (6) inch canned design motors from 5 – 40 HP will operate in water up to 95º F (35º
C), without any de-rating of horsepower, with a minimum flow rate of .5 ft./sec. past the
motor. 6" – 50 HP and all 8" – 10" motors can operate in 77º F (25º C) water with .5'/sec
velocity past the motor.
One way to make a flow sleeve is to install a well seal above the pump discharge and
slip a piece of casing over the pump and affix it to the well seal. Drill three holes at 120º
intervals on the lower section of the casing and insert (3) screws and nuts through the
casing, just touching the motor. Tighten the nuts out against the casing. Insure that the
screws do not protrude out too far as you don’t want them catching on well joints.
pump CoolING aND lubrICatIoN
In addition to motor cooling, another reason to maintain minimum flow rates is pump
lubrication. All manufacturers’, either on curves or in selection charts, show minimum
flows. This insures that rotating pump parts are properly lubricated to prolong service
life and reduce friction. A dead headed pump will super heat water very quickly, and hot
water has no lubricity.
mINImum flow ratES for propEr motor CoolING
3.75" Diameter Cp = 5.5" Dia. fE = 5.38" Dia. Cp = 7.52" Dia.
well or Sleeve 4" Cp or fE motor 6" Cp motor 6" fE motor 8" Cp motor
Diameter (inches) .25'/sec .5'/sec. .5'/sec. .5'/sec.
Gpm required
4 1.2 – – –
5 7 – – –
6 13 7 9 –
7 20 23 25 –
8 30 41 45 9
10 50 85 90 53
12 80 139 140 107
14 110 198 200 170
16 150 276 280 313
Multiply gpm by .2271 for m 3 /Hr.
Multiply gpm by 3.785 for l/min.
FLOW SLEEVE